Self-contained spring inserter for drug delivery infusion set

ABSTRACT

An infusion set includes a base ( 221 ) and a flexible catheter ( 242 ) movable from a first catheter position disposed substantially entirely within the base ( 221 ) to a second catheter position in which a free end of the catheter ( 242 ) is disposed externally of the base ( 221 ). An introducer needle ( 234 ) is located within the catheter ( 242 ) and is movable between a first introducer needle position disposed substantially entirely within the base ( 221 ) and a second introducer needle position in which a free end of the introducer needle ( 234 ) is disposed externally of the base ( 221 ). A spring ( 281 ) is activated to move the catheter ( 242 ) from the first to the second catheter position and the introducer needle ( 234 ) from the first to the second introducer needle position to facilitate insertion of the catheter ( 242 ). The introducer needle ( 234 ) is thereafter moved by the spring ( 281 ) back to the first introducer needle position to store the introducer needle ( 234 ) within the base ( 221 ) with the free end of the catheter ( 242 ) remaining disposed externally of the base ( 221 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 14/678,732entitled “Self-Contained Spring Inserter for Drug Delivery Infusion Set”filed Apr. 3, 2015, which is a continuation application of U.S. patentapplication Ser. No. 13/983,992, filed Oct. 18, 2013, which is the U.S.national stage of International Application No. PCT/US2012/000072, filedFeb. 8, 2012, which claims the benefit under 35 U.S.C. § 119(e) of U.S.Provisional Application Ser. No. 61/441,195, filed Feb. 9, 2011, theentire disclosures of all of said prior applications being incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates generally to a drug delivery infusion sethaving a self-contained inserter. More particularly, the presentinvention relates to a self-contained inserter in which the introducerneedle is stored in a base after being withdrawn from an insertion site.Still more particularly, the present invention relates to aself-contained inserter in which the introducer needle and catheter areinserted at an insertion site and the introducer needle is withdrawnfrom the insertion site by the push of a button.

BACKGROUND OF THE INVENTION

A large number of people suffering from diabetes use some form ofinsulin therapy to maintain close control of their glucose levels.Currently, there are two principal modes of daily insulin therapy. Thefirst mode includes syringes and insulin pens. These devices are simpleto use and are relatively low in cost, but they require a needle stickat each injection, typically three to four times per day. The secondmode includes infusion pump therapy, which entails the purchase of aninsulin pump that lasts for about three years. The initial cost of thepump can be significant, but from a user perspective, the overwhelmingmajority of patients who have used pumps prefer to remain with pumps forthe rest of their lives. Infusion pumps, although more complex thansyringes and pens, offer the advantages of continuous infusion ofinsulin, precision dosing and programmable delivery schedules. Thisresults in closer blood glucose control and an improved feeling ofwellness.

The use of an infusion pump further requires the use of a disposablecomponent, typically referred to as an infusion set or pump set, whichconveys the insulin from a reservoir within the pump into the skin ofthe user. An infusion set typically consists of a pump connector, alength of tubing, and a hub or base from which an infusion needle orcannula extends. The hub or base has an adhesive that retains the baseon the skin during use. The hub or base may be applied to the skinmanually or with the aid of a manual or automatic insertion device.Often, the insertion device is a separate, stand-alone unit that theuser is required to carry and provide.

There are many available versions of infusion set, including steelcannula infusion sets and soft (flexible) catheter sets. Soft cathetersets are typically inserted into a patient manually with the aid of asteel introducer needle, which is later removed from the patient leavingthe soft catheter in place. In another type of infusion set, as notedabove, a mechanized inserter is used to insert the introducer needle andcatheter, remove the introducer needle, or both. The introducer needleis completely removed from the infusion set before being connected tothe insulin pump.

One problem associated with manually inserting and retracting theintroducer needle is variability in the insertion and retraction force,speed, smoothness and angle. This variability can lead to an increasedrate of catheter insertion failure.

Further, as noted above, the user typically must remove the introducerneedle after inserting the cannula. This exposes the user to accidentalneedle sticks from handling the removed introducer needle.

To monitor blood levels, such as a blood glucose level, the usertypically must use a separate device other than the infusion set. Theuser has to carry this separate device in addition to the infusion setto check and/or monitor one's blood level. Accordingly, a need existsfor an infusion set that incorporates a sensor to measure blood levelsand facilitate insertion of the sensor.

Accordingly, a need exists for an infusion set that facilitatesinsertion of the cannula, while reducing the number of components a usermust carry and substantially preventing accidental needle sticks.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an exemplary infusionset that includes an integral introducer needle to facilitate cannulainsertion.

Another object of the present invention is to provide an infusion sethaving a self-contained introducer needle to facilitate cannulainsertion and reduce the number of components a user must carry.

Another object of the present invention is to provide an infusion set inwhich insertion of the catheter and introducer needle and retraction ofthe introducer needle is automatic, thereby substantially eliminatingvariability from the process.

Another object of the present invention is to provide an infusion sethaving a self-contained introducer needle to substantially reduce theoverall size of the infusion set.

Another object of the present invention is to provide an infusion sethaving an integrated sensor, such as a blood glucose sensor.

Another object of the present invention is to provide an infusion set inwhich separate, self-contained introducer needles facilitate cannula andsensor insertion.

In accordance with an exemplary embodiment of the present invention, adrug delivery infusion set houses and stores the introducer needle andthe means to insert and retract the introducer needle. The catheter andintroducer needle are self-contained within the body of the infusionset. The introducer needle is automatically and fully retracted with theself-contained inserter. Because the introducer needle is self-containedin the base of the infusion set, the user does not have to manuallyremove the introducer needle. Thus, user contact with the introducerneedle is avoided, thereby preventing accidental introducer needlesticks.

In accordance with another exemplary embodiment of the presentinvention, a drug delivery infusion set houses and stores a cannula fordrug delivery and a sensing element for continuously monitoring bloodlevels, both of which are self-contained within the body of the infusionset. The cannula and sensing element are both substantiallysimultaneously inserted in an injection site. The infusion setincorporates the sensing element therein, thereby reducing the amount ofequipment a user needs to carry as well as reducing the number ofprocedures the user must perform.

These and other objects are substantially achieved by providing aninfusion set having an integrated and self-contained inserter thatinserts a catheter and withdraws the introducer needle of the infusionset, thereby reducing the number of components required to be carried bythe user. Additionally, accidental introducer needle sticks aresubstantially prevented while providing a low profile infusion set.

BRIEF DESCRIPTION OF THE DRAWINGS

The above benefits and other advantages of the various embodiments ofthe present invention will be more apparent from the following detaileddescription of exemplary embodiments of the present invention and fromthe accompanying drawing figures, in which:

FIG. 1 is a perspective view of an assembled infusion set in accordancewith a first exemplary embodiment of the present invention;

FIG. 2 is a top plan view in cross-section of the infusion set of FIG.1;

FIG. 3 is a partial perspective view of the infusion set of FIG. 1;

FIG. 4 is a side perspective view in cross-section of the infusion setof FIG. 1;

FIG. 5 is a partial top plan view of the infusion set of FIG. 1;

FIG. 6 is a partial perspective view of the infusion set of FIG. 1;

FIG. 7 is a partial perspective view of the infusion set of FIG. 1;

FIG. 8 is a partial perspective view in cross-section of the infusionset of FIG. 1;

FIG. 9 is a perspective view of an infusion set according to a secondexemplary embodiment of the present invention;

FIG. 10 is a perspective view in cross-section of the infusion set ofFIG. 9;

FIG. 11 is a perspective view of the infusion set of FIG. 9 with alocking member removed;

FIG. 12 is a partial perspective view of the infusion set of FIG. 9 withthe catheter and introducer hubs in first positions;

FIG. 13 is a perspective view in cross-section of the infusion set ofFIG. 12;

FIG. 14 is a partial perspective view of the infusion set of FIG. 9 withthe catheter and introducer hubs in second positions;

FIG. 15 is a perspective view in cross-section of the infusion set ofFIG. 14;

FIG. 16 is a partial perspective view of the infusion set of FIG. 9 withthe catheter hub in the second position and the introducer hub returnedto the first position;

FIG. 17 is a perspective view in cross-section of the infusion set ofFIG. 16;

FIG. 18 is a perspective view of the infusion set of FIG. 9 with aconnector moved to a second position;

FIG. 19 is a perspective view of the infusion set of FIG. 18 with theconnector rotated prior to removal thereof;

FIG. 20 is a perspective view of the infusion set of FIG. 19 with theconnector removed from a base of the infusion set;

FIG. 21 is a perspective view in cross-section of the base of theinfusion set showing first and second ends of a torsion spring;

FIG. 22 is a lower perspective view of the connector;

FIG. 23 is a perspective view of an infusion set with a sensing elementin accordance with a third exemplary embodiment of the presentinvention;

FIG. 24 is a perspective view of the infusion set of FIG. 23 with alocking member removed;

FIG. 25 is a bottom plan view of the infusion set of FIG. 23;

FIG. 26 is a partial top plan view of the infusion set of FIG. 23;

FIG. 27 is a partial perspective view of the infusion set of FIG. 23;

FIG. 28 is an enlarged perspective view of a linking arm of FIG. 27;

FIG. 29 is a partial perspective view in cross-section of the infusionset of FIG. 23 showing an introducer needle and catheter;

FIG. 30 is a partial perspective view in cross-section of the infusionset of FIG. 23 showing a drive and slave gear arrangement;

FIG. 31 is a partial perspective view in cross-section of the infusionset of FIG. 23 showing a fluid path;

FIG. 32 is another partial perspective view in cross-section of theinfusion set of FIG. 31 showing a fluid path;

FIG. 33 is a perspective view of the infusion set of FIG. 23 showingcatheter and introducer hubs in a first position;

FIG. 34 is a perspective view of the infusion set of FIG. 23 showing thecatheter hub in a second position and the introducer hub returned to thefirst position;

FIG. 35 is a bottom plan view of the infusion set of FIG. 23 with acannula and sensing element exposed;

FIG. 36 is partial a top plan of an infusion set in accordance with afourth exemplary embodiment showing an infusion set having two sets ofhubs; and

FIG. 37 is a partial perspective view of the infusion set of FIG. 35;

FIG. 38 is a partial perspective view of the infusion set of FIG. 35showing the hub set connected to a slave gear;

FIG. 39 is a partial perspective view of the infusion set of FIG. 35showing an introducer hub in a second position and a sensing element hubslightly withdrawn from the second position; and

FIG. 40 is a partial top plan view of an infusion set in accordance witha fifth exemplary embodiment of the present invention.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components and structures.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The exemplary embodiments of the present invention described belowprovide a novel means of inserting a soft catheter into the skin. Forexample, exemplary embodiments of the present invention provide anintegrated inserter that inserts a soft catheter into the skin andwithdraws the introducer needle into a base of an infusion set, as shownin FIGS. 1-8, while maintaining a low profile infusion set.

A base 121 of an infusion set 101, as shown in FIG. 1, is preferablyprovided with a skin-securing, adhesive layer (202 in FIG. 20) to securethe infusion set to the skin surface at a desired catheter insertionsite. The adhesive layer ensures that the base is at the proper positionrelative to the skin surface, and that the skin is secured duringinsertion to further aid introducer needle insertion with a reduced riskof tenting of the skin surface. The base has a first recess 122 and asecond recess (not shown) adapted to receive tabs of a fluid connector111, thereby securing the fluid connector 111 to the base 121 to fullyassemble the infusion set 101, as shown in FIG. 1. A first rampedsurface 125 slopes downwardly and outwardly toward the first recess 122,as shown in FIG. 6, thereby facilitating the connector tab to slide downinto the first recess and creating a snap-fit connection. Rampedsurfaces 126 slope outwardly at opposite ends of the first recess 122,as shown in FIG. 7, thereby allowing the fluid connector 111 to berotated with respect to the base 121 to allow the connector tabs to bereleased from the base recesses to disconnect the connector 111 from thebase 121.

An introducer hub 131 is movably disposed in the base 121 of theinfusion set 101, as shown in FIG. 2. An upper portion 132 of theintroducer hub 131 has an opening 133 connected to a flexible introducerneedle 134 rigidly connected to a lower portion 135 of the introducerhub 131, as shown in FIGS. 3 and 5. The upper portion 132 of theintroducer hub 131 is disposed between guide rails 123 and 124 of thebase 121, as shown in FIGS. 5 and 6, to guide linear movement of theintroducer hub 131. The introducer hub 131 is movable from a firstposition shown in FIG. 5, to a second position shown in FIG. 7, and backto the first position shown in FIG. 5. When the introducer hub 131 is inthe first position, the introducer needle 134 is disposed within thebase 121 as shown in FIG. 4, thereby preventing any accidentalintroducer needle sticks. When the introducer hub 131 is in the secondposition, the introducer needle 134 is exposed outside of the base 121as shown in FIG. 7 such that a patient's skin can be pierced to insertan angled catheter 142.

A catheter hub 141 abuts the lower portion 135 of the introducer hub131, as shown in FIGS. 2 and 3. The flexible catheter 142 is rigidlyconnected to the catheter hub 141. The introducer needle 134 is movablydisposed within the catheter 142, as shown in FIG. 4. Linear movement ofthe introducer hub 131 results in linear movement of the catheter hubbecause of the engagement the lower portion 135 of the introducer hub131 and the catheter hub 141. The catheter hub 141 is movable between afirst position shown in FIGS. 5 and 6, and a second position shown inFIG. 7. When the catheter hub 141 is in the first position, the catheter142 is disposed within the base 121. When the catheter hub 141 is movedto the second position, the catheter 142 is moved out of the base 121and is insertable at an angle under the surface of a patient's skin.

A disc 171 is rotatably disposed in the base 121, as shown in FIGS. 2-8.The disc 171 has an inner perimeter 172 forming an aperture therethroughand an outer perimeter 173. A torsion spring 181 is disposed within theinner perimeter 172 of the disc 171. Preferably, the torsion spring 181is a 360 degree torsion spring, i.e., the torsion spring causes the disc171 to rotate 360 degrees upon release. First and second recesses 174and 175 are formed in the outer perimeter 173 of the disc 171. Anopening 176 is formed in an upper surface 177 of the disc, as shown inFIG. 4 and receives a first protrusion 152 of a linking arm 151.

The torsion spring 181 has a first end rigidly fixed to the base 121. Asecond end 183 of the torsion spring 181 is fixed to the disc 171, asshown in FIGS. 2 and 3. An opening 184 can be formed in the disc 171 toreceive the torsion spring.

The linking arm 151 connects the disc 171 to the introducer hub 131,thereby converting rotational movement of the disc 171 into linearmovement of the introducer hub 131. The first protrusion 152 of thelinking arm 151 extends downwardly proximal a first end 155 of thelinking arm 151, as shown in FIGS. 3 and 4. A second protrusion 153extends upwardly from a second end of the linking arm 151 and isreceived by an opening 137 in the introducer hub 131.

The button 161 is movable between a first, or up, position as shown inFIG. 1, and a second, or lower, position as shown in FIG. 4. Tabs 162and 163 extend inwardly from free ends of arms 164 and 165 extendingdownwardly from an upper surface 166 of the button, as shown in FIGS.1-3. When the button 161 is in the first position, as shown in FIGS. 1and 2, the tabs 162 and 163 are received within the recesses 174 and 175of the disc 171, thereby preventing rotational movement of the disc 171.When the button 161 is pressed downwardly to the second position, asshown in FIG. 3, the tabs 162 and 163 are moved downwardly below thedisc 171 such that the tabs are no longer disposed in the disc recesses174 and 175, thereby allowing the disc 171 to rotate due to the torqueapplied by the torsion spring.

Snap arms 167 and 168 extend downwardly from the button 161, as shown inFIGS. 2 and 6. Hooks disposed at the free ends of the snap arms 167 and168 are received in upper recesses (not shown) in the base 121, therebymaintaining the button 161 in the up position shown in FIG. 1. When thecatheter 142 is to be inserted, the button 161 is pushed downwardly tothe second position and the snap arms 167 and 168 move from the upperrecesses to lower recesses (not shown) in the base 121. The snapconnection between the button snap arms 167 and 168 and the lowerrecesses in the base 121 maintains the button 161 connected to the base121 after inserting the catheter 142.

An angled guide 191 is provided in the base 121 to guide movement of theintroducer needle 134 and the catheter 142. The angled guide 191 createsan angle with respect to the surface of the skin of betweenapproximately 30 and 45 degrees, inclusive, and preferably about 45degrees. An opening 196 is formed in the base at the end of the angledguide 191 to allow the introducer needle 134 and catheter 142 to exitthe base. First and second flexible arms 192 and 193 extend in the base121 in the direction of movement of the catheter hub 141. Upwardlyextending hooks 194 and 195 are disposed at an end of the flexible arms.

A septum 197 is disposed in an upper surface 127 of the base 121, asshown in FIGS. 4 and 8. Preferably, the septum 197 has a slit 198 tofacilitate receiving a penetrating member, or sharp, 199 of theconnector 111, as shown in FIG. 4, although the slit may not be requiredin some cases. A groove 128 is formed in an upper surface of theintroducer hub 131, as shown in FIG. 8, and having one end at theintroducer hub opening 133.

The fluid connector 111 has first and second flexible arms 112 and 113,as shown in FIGS. 1-3, that engage the first and second recesses 122 inthe base 121 to secure the connector to the base. Tubing 114 extendsfrom the fluid connector 111 and is adapted to connect to a pump. Thetubing 114 is connected to a penetrating member 199 extending downwardlyfrom the fluid connector 111, and a fluid path is formed therebetween.The penetrating member 199 is adapted to penetrate the septum 197 whenthe fluid connector 111 is connected to the base 121, as shown in FIG.4.

Assembly and Operation

FIG. 1 is a perspective view of the infusion set 101 ready to beinserted by a user. The fluid connector 111 is secured to the base 121by engaging the hooks of arms 112 and 113 in the base recesses 122, asshown in FIGS. 1 and 3. Ramped surfaces 125 in the base 121 facilitateengaging the connector arms 112 and 113 with the base recesses 122.

The button 161 is in the up, or first, position, as shown in FIG. 1. Inthis position, the button tabs 162 and 163 are disposed in the discrecesses 174 and 175, thereby preventing rotation of the disc 171. Thelinking arm 151 is aligned with the longitudinal axis of the catheter142, as shown in FIG. 2. The catheter hub 141 and the introducer hub 131are disposed to the right of the base 121 spaced from the hooks 194 and195 of the base flexible arms 192 and 193, as shown in FIGS. 2 and 3.The catheter 142 and the introducer needle 134 are disposed within thebase 121, thereby substantially preventing accidental introducer needlesticks.

Adhesive backing (not shown) is removed from the base 121 to expose anadhesive layer (202 in FIG. 20) on a lower surface of the base, suchthat the base can be firmly secured to a desired location on the skin.To insert the catheter 142, the button 161 is pushed downwardly to adown, or second, position to release the torsion spring 181, therebydriving rotational movement of the disc 171. The downward movement ofthe button 161 moves the button tabs 162 and 163 out of the discrecesses 174 and 175, thereby freeing the disc 171 to rotate. The buttonsnap arms 167 and 168 move from the upper recesses to the lower recessesin the base 121, thereby securing the button 161 to the base 121. Thesecond end 183 of the torsion spring 181 rotates with the disc 171.

As the disc 171 begins to rotate counter-clockwise as shown in FIGS. 2,3, 5 and 6, the linking arm 151 moves with the disc. The movement of thelinking arm 151, in turn, results in linear movement of the introducerhub 131. The introducer hub 131 is limited to linear movement by theguide rails 123 and 124, as shown in FIG. 5. The linear movement of theintroducer hub 131 pushes the catheter hub 141 from a position shown inFIG. 6 to a position shown in FIG. 7. The introducer hub 131 pushes thecatheter hub 141 along the base flexible arms 192 and 193 such that thecatheter hub 141 flexes the arms 192 and 193 downwardly to pass over thehooks 194 and 195. After the catheter hub 141 passes over the hooks 194and 195, the hooks snap back up to prevent rearward movement of thecatheter hub 141 back along the flexible arms 192 and 193. Stops 103 and104 disposed in the base 121 prevent further forward linear movement bythe catheter hub 141. Additionally, the forward linear movement of thecatheter hub 141 and the introducer hub 131 results in forward movementof the catheter 142 and the introducer needle 134, respectively. Thecatheter 142 is fixedly attached to the catheter hub 141 and theintroducer needle 134 is fixedly attached to the introducer hub 131. Theangled guide 191 in the base guides the downwardly angled movement ofthe catheter 142 and introducer needle 134. The introducer needle 134extends beyond the catheter 142 such that the introducer needle piercesthe surface of the skin to allow the catheter to be inserted at an anglebeneath the surface of the skin. The disc 171 has rotated approximately180 degrees at this point.

As the disc 171 continues to rotate past the 180 degree point, thelinking arm 151 causes the introducer hub 131 to move linearlyrearwardly between the guide rails 123 and 124. The hooks 194 and 195 ofthe base flexible arms 192 and 193 prevent rearward movement of thecatheter hub 141. The rearward linear movement of the introducer hub 131pulls the introducer needle 134 out of the insertion site, leaving thecatheter 142 inserted at an angle beneath the surface of the skin. Asthe disc 171 continues to rotate to the 360 degree point, the introducerneedle 134 is withdrawn entirely into the base 121 of the infusion set101. The torsion spring 181 can be pre-loaded such that the disc 171does not rotate more than approximately 360 degrees. Additionally, astop tab (not shown) can be disposed in the base that mates with acorresponding stop tab (not shown) on the disc to prevent the disc fromrotating more than approximately 360 degrees. The infusion set 101 isnow ready to begin infusing insulin.

A fluid path is created from the connector tubing 114, through theseptum 197, into the groove 128 of the introducer hub 131, through theopening 133 in the introducer hub 131, into the introducer needle 134and into the catheter 142, as shown in FIGS. 4 and 8. The groove 128 iscompletely sealed by a lower surface 110 of the septum 197, as shown inFIG. 8. Furthermore, the groove 128 is completely sealed by the lowersurface 110 of the septum 197 over the entire range of motion of theintroducer hub 131, thereby forming a dynamic seal.

The fluid connector 111 and tubing 114 can be easily removed by rotatingthe connector relative to the base 121. The hooks of the connector arms112 and 113 slide along the ramped surfaces 126 of the base recesses122, allowing the connector 111 to be easily disconnected from the base.The fluid connector 111 can then be reconnected when desired asdescribed above.

The pre-loaded torsion spring 181, when released by the button 161,performs both the insertion and retraction of the introducer needle 134.Torsion springs can store a large amount of energy within a small andflat profile. This is facilitated by the 360 degree rotation of the disc171 driven by the torsion spring 181. The first 180 degree rotation ofthe disc 171 inserts the introducer needle 134, and the second 180degree rotation of the disc retracts the introducer needle completelyinto the base 121. The torsion spring 181 can be pre-loaded to not lessthan 180 degrees and up to approximately 360 degrees to perform theinsertion and retraction of the introducer needle.

The linking arm 151 between the introducer hub 131 and the disc 171produces a cyclical piston movement. By using a flexible or bendingintroducer needle 134 and an angled catheter 142, the infusion set canhave a low profile. The angled guide 191 in the base 121 guides theintroducer needle downwardly into the surface of the skin. Moreover, theonly action required by the user to press the button 161 downwardly. Theinsertion of the introducer needle 134 and the catheter 142 andretraction of the introducer needle occurs automatically. Additionally,by only requiring the user to push the button 161 downwardly, theinfusion set 101 can be positioned and used in hard to reach and awkwardbody locations.

The septum 197 is disposed approximately in the center of the base 121,thereby allowing multiple orientations when connecting the connector 111to the base 121. The sliding septum design between the linearly movingintroducer hub 131 and the lower portion 110 of the septum 197 allowsfor the septum to be centered on the base 121.

The exemplary embodiment described above can be adapted for use witheither intradermal or subcutaneous injections. In addition, a differentmethod of maintaining the fluid connection is possible other thanthrough the penetrating member 199 and septum 197. For example, a coiledtube connected to the introducer hub 131 that extends during insertionof the introducer needle 134, and then recoils upon retraction of theintroducer needle, can be used. Alternative methods may be used toinsert the catheter and introducer needle. For example, an angled needlein contact with the skin and driven at a smaller angle can be used toenter the intradermal layer of the skin. Alternative methods ofconnecting the connector to the base can be used to facilitateconnecting and disconnecting of the connector.

Although the exemplary embodiment described above is an infusion set, itwill be apparent to those of ordinary skill in the art that theprinciples of the present invention are also applicable to patch pumps(self-contained infusion devices with integral reservoirs and pumpingmechanisms) and other types of medical infusion and injection devices.

Second Exemplary Embodiment

An infusion set 201 in accordance with a second exemplary embodiment ofthe present invention is shown in FIGS. 9-22. A base 221 of the infusionset 201, as shown in FIG. 9, is preferably provided with askin-securing, adhesive layer 202 (FIG. 20) to secure the infusion setto the skin surface at a desired catheter insertion site. The adhesivelayer ensures that the base 221 is at the proper position relative tothe skin surface, and that the skin is secured during insertion tofurther aid introducer needle insertion with a reduced risk of tentingof the skin surface. The base has a first recess 222 and a second recess(not shown) adapted to receive tabs of a fluid connector 211, therebysecuring the fluid connector 211 to the base 221 to fully assemble theinfusion set 201, as shown in FIG. 9. A first ramped surface 225 (FIG.20) slopes downwardly and outwardly toward the first recess 222, therebyfacilitating the fluid connector tab to slide down into the first recessand creating a snap fit connection. A second ramped surface 226 (FIG.20) slopes outwardly at an end of the first recess 222, thereby allowingthe fluid connector 211 to be rotated with respect to the base 221 toallow the connector tabs to be released from the base recesses 222 todisconnect the fluid connector 211 from the base 221, as shown in FIG.20.

An introducer hub 231 is movably disposed in the base 221 of theinfusion set 201, as shown in FIG. 12. The introducer hub 231 has anopening 233 to receive an introducer needle 234, as shown in FIGS. 10and 15. A lower portion 232 of the introducer hub 231 is disposedbetween guide rails 223 and 224 of the base 221, as shown in FIG. 12, toguide linear movement of the introducer hub 231. The introducer hub 231is movable from a first position shown in FIG. 12, to a second positionshown in FIG. 14, and back to the first position shown in FIG. 16. Whenthe introducer hub 231 is in the first position, the introducer needle234 is disposed within the base 221, thereby preventing any accidentalintroducer needle sticks. When the introducer hub 231 is in the secondposition, the introducer needle 234 is exposed outside of the base 221such that a patient's skin can be pierced to insert an angled catheter242.

A catheter hub 241 abuts the introducer hub 231, as shown in FIGS.12-15. The flexible catheter 242 is rigidly connected to the catheterhub 241. The introducer needle 234 is movably disposed within thecatheter 242, as shown in FIGS. 10 and 15. Linear movement of theintroducer hub 231 results in linear movement of the catheter hub 241because of the engagement of the introducer hub 231 with the catheterhub 241. The catheter hub 241 is movable between a first position shownin FIG. 12, and a second position shown in FIG. 14. When the catheterhub 241 is in the first position, the catheter 242 is disposed withinthe base 221, as shown in FIG. 13. When the catheter hub 241 is moved tothe second position, the catheter 242 is moved out of the base 221, asshown in FIG. 15, and is insertable at an angle under the surface of apatient's skin.

A disc 271 is rotatably disposed in the base 221, as shown in FIGS. 10and 12-18. The disc 271 has an inner perimeter 272 forming an aperturetherethrough and an outer perimeter 273, as shown in FIGS. 10, 12 and14. A torsion spring 281 is connected to the disc 271. Preferably, thetorsion spring 281 is a 360 degree torsion spring, i.e., the torsionspring 281 causes the disc 271 to rotate 360 degrees upon release. Firstand second recesses 274 and 275 are formed in the outer perimeter 273 ofthe disc 271, as shown in FIG. 14. An opening 276 is formed in an uppersurface 277 of the disc, as shown in FIG. 14 and receives a first end252 of a linking arm 251.

The torsion spring 281 has a first end 282 rigidly fixed to the base221, as shown in FIG. 21. A second end 283 of the torsion spring 281 isfixed to the disc 271, as shown in FIGS. 14 and 21. An opening 284 canbe formed in the disc 271 to receive the second end 283 of the torsionspring 281.

The linking arm 251 connects the disc 271 to the introducer hub 231,thereby converting rotational movement of the disc 271 into linearmovement of the introducer hub 231. The first end 252 of the linking arm251 is connected to the disc 271, as shown in FIGS. 12 and 14-16. Asecond end 253 of the linking arm 251 is connected to the introducer hub231.

The fluid connector 211 is movable between a first, or up, position asshown in FIGS. 9, 10 and 13, and a second, or down, position as shown inFIGS. 15 and 17. The fluid connector 211 is removably connected to thebase 221 such that the fluid connector 211 can be removed after thecatheter 234 has been inserted, as shown in FIG. 20. Tabs 262 and 263extend inwardly from free ends of arms 264 and 265 extending downwardlyfrom an upper surface 266 of the connector 211, as shown in FIGS. 20 and22. When the connector 211 is in the first position, as shown in FIGS.9, 10 and 13, tabs extending downwardly from first and second lockingears 205 and 207 (FIG. 20) are received within the recesses 274 and 275of the disc 271, thereby preventing rotational movement of the disc 271.When the connector 271 is pressed downwardly to the second position, asshown in FIGS. 15 and 17, a shoulder 203 (FIG. 22) of a downwardlyextending post 209 of the connector engages the upper surface of theseptum assembly 297, thereby pushing the septum assembly 297 downwardlyand disengaging the locking tabs on the septum assembly 297 fromrecesses in the inner perimeter 272 of the disc 271. When the tabs ofthe septum assembly 297 are not received by the recesses in the innerperimeter of the disc 271, the disc 271 can rotate due to the torqueapplied by the torsion spring 281.

Arms 264 and 265 extend downwardly from the connector 211, as shown inFIGS. 20 and 22. Tabs 262 and 263 disposed at the free ends of the arms264 and 265 are received on the ramps 225 of the base 221, therebymaintaining the connector 211 in the up position shown in FIG. 9. Whenthe catheter 242 is to be inserted, a locking member 267 is removed suchthat the fluid connector 211 can be pushed downwardly to the secondposition. The downward movement of the fluid connector 211 flexes thearms 264 and 265 outwardly such that the arms 264 and 265 slide down theramps 225 into the recesses 222 in the base 221. The snap connectionbetween the connector arms 264 and 265 and the recesses 222 in the base221 retains the fluid connector 221 connected to the base 221 afterinserting the catheter 242.

An angled guide 291 is provided in the base 221 to guide movement of theintroducer needle 234 and the catheter 242, as shown in FIGS. 10 and 12.The angled guide 291 creates an angle with respect to the surface of theskin of between approximately 30 and 45 degrees, inclusive, andpreferably about 45 degrees. An opening 296 is formed in the base 221 atthe end of the angled guide 291 to allow the introducer needle 234 andcatheter 242 to exit the base 221. First and second flexible arms 292and 293 extend in the base 221 in the direction of movement of thecatheter hub 241, as shown in FIGS. 12, 14 and 16. Upwardly extendinghooks 294 and 295 are disposed proximate an end of each of the flexiblearms 292 and 293. Stop members 238 and 239 are disposed at the ends ofeach of the flexible arms 292 and 293, as shown in FIG. 12. Recesses 245and 246 are formed on each flexible arm 292 and 293 between the hooks294 and 295 and the stop members 238 and 239, respectively, to receivethe catheter hub 241 in the second position.

A septum 297 is disposed in the aperture formed in the disc 271, asshown in FIG. 12. Preferably, the septum 297 has a slit to facilitatereceiving a penetrating member, or sharp, of the fluid connector 211, asshown in FIG. 15, although the slit may not be required in some cases.

The fluid connector 211 has first and second flexible arms 264 and 265,as shown in FIGS. 9, 11 and 22, that engage the first and secondrecesses 222 in the base 221 to secure the fluid connector 211 to thebase 221. Tubing 214 extends from the connector 211 and is adapted toconnect to a pump (not shown). The tubing 214 is connected to apenetrating member extending downwardly from the post 209 of theconnector 211, and a fluid path is formed therebetween. The penetratingmember 299 is adapted to penetrate the septum 297 when the connector 211is connected to the base 221, as shown in FIGS. 10 and 15.

FIG. 9 is a perspective view of the infusion set 201 ready to beinserted by a user. A tab 206 on the base 221 is received by a recess208 in the fluid connector, as shown in FIGS. 9 and 22, to preventaccidental removal of the fluid connector 211 from the base 221 prior toan insertion procedure. The locking member 267 is disposed between thebase 221 and the connector 211 to prevent accidentally activating thetorsion spring 281 and exposing the needle 234 and catheter 242 prior toa desired insertion procedure.

The fluid connector 211 is in the up, or first, position, as shown inFIG. 9. In this position, the locking tabs of the septum assembly 297are disposed in the recesses in the inner perimeter 272 of the disc 271,thereby preventing rotation of the disc 271. The catheter hub 241 andthe introducer hub 231 are disposed to the right of the base 221 spacedfrom the hooks 294 and 295 of the base flexible arms 292 and 293, asshown in FIG. 12. The catheter 242 and the introducer needle 234 aredisposed within the base 221, thereby substantially preventingaccidental introducer needle sticks.

An adhesive backing (not shown) is removed from the base 221 to exposean adhesive layer 202 (FIG. 20) on a lower surface of the base, suchthat the base can be firmly secured to a desired location on the skin.To insert the catheter 242, the locking member 267 is removed as shownin FIG. 11 such that the fluid connector 211 can be pushed downwardly toa second, or down, position to release the torsion spring 281, therebydriving rotational movement of the disc 271. The downward movement ofthe connector 211 causes the shoulder 203 of the connector post 209 toengage the septum assembly 297 and push the septum assembly 297downwardly, thereby moving the locking tabs of the septum assembly 297out of engagement with recesses in the inner perimeter 272 of the disc271, which frees the disc 271 to rotate. The connector arms 264 and 265move from the ramp 225 to the recesses 222 in the base 221, therebysecuring the fluid connector 211 to the base 221. The second end of thetorsion spring 281 rotates with the disc 271 as the torsion spring 281causes the disc 271 to rotate.

As the disc 271 begins to rotate counter-clockwise as shown in FIGS. 12,14 and 16, the linking arm 251 moves with the disc 271. The movement ofthe linking arm 251, in turn, results in linear movement of theintroducer hub 231. The introducer hub 231 is limited to linear movementby the guide rails 223 and 224, as shown in FIG. 12. The linear movementof the introducer hub 231 pushes the catheter hub 241 from the firstposition shown in FIG. 12 to the second position shown in FIG. 14. Theintroducer hub 231 pushes the catheter hub 241 along the base flexiblearms 292 and 293 such that the catheter hub 241 flexes the arms 292 and293 downwardly to pass over the hooks 294 and 295. After the catheterhub 241 passes over the hooks 294 and 295, the hooks snap back up toprevent rearward movement of the catheter hub 241 back along theflexible arms 292 and 293. Stop members 238 and 239 disposed at ends ofthe arms 292 and 293 prevent further forward linear movement by thecatheter hub 241. Additionally, the forward linear movement of thecatheter hub 241 and the introducer hub 231 results in forward movementof the catheter 242 and the introducer needle 234, respectively. Thecatheter 242 is fixedly attached to the catheter hub 241 and theintroducer needle 234 is fixedly attached to the introducer hub 231. Theangled guide 291 in the base guides the downwardly angled movement ofthe catheter 242 and introducer needle 234. The introducer needle 234extends beyond the catheter 242 such that the introducer needle 234pierces the surface of the skin to allow the catheter 242 to be insertedat an angle beneath the surface of the skin. The catheter hub 241 issecurely received between the hooks 294 and 295 and the stop members 238and 239 to prevent rearward linear movement of the catheter hub 241after the catheter 242 has been inserted. The disc 271 has rotatedapproximately 180 degrees at this point, as shown in FIG. 14.

As the disc 271 continues to rotate past the 180 degree point, thelinking arm 251 causes the introducer hub 231 to move linearlyrearwardly between the guide rails 223 and 224. The hooks 294 and 295 ofthe base flexible arms 292 and 293 prevent rearward movement of thecatheter hub 241. The rearward linear movement of the introducer hub 231pulls the introducer needle 234 out of the insertion site, leaving thecatheter 242 inserted at an angle beneath the surface of the skin, asshown in FIG. 16. As the disc 271 continues to rotate, the introducerneedle 234 is withdrawn entirely into the base 221 of the infusion set201. The torsion spring 281 can be pre-loaded such that the disc 271does not rotate more than approximately 360 degrees. Additionally, astop tab (not shown) can be disposed in the base that mates with acorresponding stop tab (not shown) on the disc 271 to prevent the discfrom rotating more than approximately 360 degrees. The infusion set 201is now ready to begin infusing insulin.

A fluid path is created from the connector tubing 214, through theseptum 297, through the post 209, through the base tubing 228 fluidlyconnecting the septum 297 and the introducer hub 231, through theintroducer needle 234 and into the catheter 242, as shown in FIG. 17.The base tubing 228 is flexible such that the base tubing 228 moves withthe introducer hub 231 between first and second positions, as shown inFIGS. 12, 14 and 16.

The connector 211 and tubing 214 can be easily removed by rotating theconnector 211 relative to the base 221, as shown in FIGS. 19 and 20. Thehooks of the connector arms 264 and 265 slide along the ramped surfaces226 of the base recesses 222 causing the arms 264 and 265 to flexoutwardly, thereby allowing the connector 211 to be easily disconnectedfrom the base 221. The connector 211 can then be reconnected whendesired as described above.

The pre-loaded torsion spring 281, when released by the connector 211,performs both the insertion and retraction of the introducer needle 234.Torsion springs can store a large amount of energy within a small andflat profile. This is facilitated by the 360 degree rotation of the disc271 driven by the torsion spring 281. The first 180 degree rotation ofthe disc 271 inserts the introducer needle 234, and the second 180degree rotation of the disc retracts the introducer needle completelyinto the base 221. The torsion spring 281 can be pre-loaded to not lessthan 180 degrees and up to approximately 360 degrees to perform theinsertion and retraction of the introducer needle 234.

The linking arm 251 between the introducer hub 231 and the disc 271produces a cyclical piston movement. By using a flexible or bendingintroducer needle 234 and an angled catheter 242, the infusion set 201can have a low profile. The angled guide 291 in the base 221 guides theintroducer needle 234 downwardly into the surface of the skin. Moreover,the only action required by the user is to press the connector 211downwardly. The insertion of the introducer needle 234 and the catheter242 and the retraction of the introducer needle occur automatically.Additionally, by only requiring the user to push the connector 211downwardly, the infusion set 201 can be positioned and used inhard-to-reach and awkward body locations.

The exemplary embodiment described above can be adapted for use witheither intradermal or subcutaneous injections. Alternative methods ofconnecting the fluid connector 211 to the base 221 can also be used tofacilitate connecting and disconnecting of the fluid connector, such asa fluid connector connectable to a side of the base 221.

Although the exemplary embodiment described above is an infusion set, itwill be apparent to those of ordinary skill in the art that theprinciples of the present invention are also applicable to patch pumps(self-contained infusion devices with integral reservoirs and pumpingmechanisms) and other types of medical infusion and injection devices.

Third Exemplary Embodiment

In accordance with a third exemplary embodiment of the present inventionshown in FIGS. 23-35, an infusion set 301 includes an integral catheter342 and blood glucose sensing element 372. Suitable types ofelectromechanical sensing elements are disclosed in U.S. Pat. Nos.5,390,671, 5,391,250, 5,482,473, and 5,586,553, which are herebyincorporated by reference in their entirety. A pre-loaded torsion spring381 inserts the catheter 342 and the sensing element 372. By integratingthe sensing element 372 with the infusion set 301, the amount ofequipment required to be carried by a user is reduced, as well asreducing the number of procedures a user must perform. The torsionspring 381 substantially simultaneously drives the insertion of twosharps, i.e., a catheter introducer needle 334 and the sensing element372. The sensing element 372 can be a glucose oxidase sensor, a glucosebinding protein sensor, or any other suitable sensor, and can be usedeither to allow intermittent user readings of blood glucose levels,closed loop control of infusion pump operation based on measured bloodglucose levels (i.e., continuous glucose monitoring), or both.

As shown in FIG. 26, the infusion set 301 has a housing or base 302 inwhich a drive gear 303 and a slave gear 304 are disposed. The drive gear303 inserts and retracts the catheter introducer needle 334 and thecatheter 342. The slave gear 304 inserts the sensing element 372. Thecatheter 342 and catheter introducer needle 334 are preferably flexible.The sensing element 372 is preferably a flexible sharps.

The drive gear 303 is connected to the torsion spring 381. A first end382 of the torsion spring is connected to the housing 302 and a secondend 383 of the torsion spring is connected to the drive gear 303, asshown in FIGS. 25 and 26. Preferably, a recess 384 in an upper surface305 of the drive gear 303 receives the second end 383 of the torsionspring 381. A plurality of teeth 306 extend outwardly from an outerperimeter of the drive gear 303. Preferably, the plurality of teeth 306extend continuously around the entire outer perimeter of the drive gear303.

The slave gear 304 is disposed adjacent the drive gear 303 in thehousing 302 such that teeth 307 of the slave gear 304 engage the drivegear teeth 306, as shown in FIGS. 26 and 30. Preferably, the slave gearteeth 307 extend continuously on a portion of an outer perimeter of theslave gear 304. Preferably, the slave gear teeth 307 extendapproximately 180 degrees around the outer perimeter of the slave gear304.

A catheter linking arm 351 has a first end 352 connected to the drivegear 303 and a second end 353 connected to a catheter introducer hub341, as shown in FIGS. 26-29. Guide rails 354 and 355 in the housing 302facilitate linear movement of the catheter introducer hub 341, as shownin FIG. 30.

A sensing element linking arm 361 has a first end 362 connected to theslave gear 304 and a second end connected to a sensing element hub 371,as shown in FIG. 26. The sensing element linking arm 361 is connected tothe slave gear 304 in a substantially similar manner to the connectionbetween the catheter linking arm 351 and the drive gear 303. The sensingelement 372 is preferably a flexible sharp. Guide rails 364 and 365 inthe housing 302 facilitate linear movement of the sensing element hub371, as shown in FIG. 30.

A locking member 391 has outwardly extending first and second tabs 392and 393, as shown in FIGS. 23 and 24. The locking tabs 392 and 393 passthrough openings 308 and 309 in the housing 302 and are received byrecesses 310 and 311 in the drive and slave gears 303 and 304,respectively, as shown in FIG. 25. A friction fit is created between thelocking tabs 392 and 393 and the openings 308 and 309 in the housing302. The locking tabs 392 and 393 prevent rotation of the drive andslave gears 303 and 304 when the locking tabs 392 and 393 are receivedby the recesses 310 and 311 in the drive and slave gears 303 and 304,respectively. Removing the locking member 391, as shown in FIG. 24,disengages the tabs 392 and 393 from the drive and slave gear recesses310 and 311, thereby allowing the torsion spring 381 to rotate the driveand slave gears 303 and 304.

An angled guide 395 is provided in the housing 302 to guide movement ofthe introducer needle 334 and the catheter 342, as shown in FIG. 29. Theangled guide 395 creates an angle with respect to the surface of theskin of between approximately 30 and 45 degrees, inclusive, andpreferably about 45 degrees. An opening 396 is formed in the housing 302at the end of the angled guide 395 to allow the introducer needle 334and catheter 342 to exit the housing 302.

First and second flexible arms 385 and 386 extend in the housing 302 inthe direction of movement of the catheter hub 331, as shown in FIGS. 26and 27. Upwardly extending hooks 387 and 388 are disposed at an end ofthe flexible arms 385 and 386. A substantially similar second angledguide 397 is disposed in the housing 302 to guide the sensing element372 through an opening 398. Preferably, the angled guides 395 and 397are disposed at an angle α with respect to each other, as shown in FIGS.26 and 35. The angle α is preferably approximately 45 degrees tomaximize the distance between the point of entry into the skin betweenthe catheter 342 and the sensing element 372. This minimizes the directeffect of the insulin being administered on the measured blood glucoselevel.

A fluid connector 321 is removable connected to the housing 302, asshown in FIGS. 23-25 and 35. Tubing 314 from the fluid connector 321 isconnected to a pump (not shown) to supply medicament to the infusion set301. A penetrating member 317 of the fluid connector 321 pierces aseptum 315 disposed in the housing 302 to provide a fluid path from thepump to the infusion set 301. Tabs 322 and 323 of the fluid connector321 are received by recesses 324 and 325 in the housing 302, as shown inFIGS. 25 and 26. Finger grips 376 and 377 of the fluid connector 321facilitate a user's grip on the housing 302. The finger grips 376 and377 can be squeezed together to unlock the tabs 322 and 323 from thehousing recesses 324 and 325 to remove the fluid connector 321 from thehousing 302.

When the infusion set is ready to be used, an adhesive backing (notshown) is removed from the housing such that the housing can be disposedon the user's body at a desired location. Finger grips 376 and 377connected to the housing 302 facilitate the user's grip on the housing302 while removing the locking member 391. The locking member 391 isremoved from the housing 302, such that the locking tabs 392 and 393 aredisengaged from the recesses 310 and 311 in the drive and slave gears303 and 304, respectively. The drive and slave gears 303 and 304 arefree to rotate after the locking tabs 392 and 393 are removed from therecesses 310 and 311.

The torsion spring 381 causes the drive gear 303 to rotate when thelocking tabs 392 and 393 have been removed from the recesses 310 and311. The introducer hub 341 and catheter hub 331 are initially in afirst position, as shown in FIG. 26, proximate the drive gear 303. Asthe drive gear 303 rotates, the catheter linking arm 351 converts therotation of the drive gear 303 into linear movement of the catheterintroducer hub 341. The catheter linking arm 351 moves the catheterintroducer hub 341 linearly away from the drive gear 303, as shown inFIG. 23. The catheter introducer hub 341 pushes the catheter hub 331 asthe catheter introducer hub 341 moves away from the drive gear 303. Theguide rails 354 and 355 facilitate linear movement of the catheterintroducer hub 341 and catheter hub 331, as shown in FIG. 30.

Rotation of the drive gear 303 rotates the slave gear 304 due to theengagement between the drive gear teeth 306 and the slave gear teeth307. The sensing element linking arm 361 moves the sensing element hub371 as the slave gear 304 is rotated by the drive gear 303. The guiderails 364 and 365 facilitate linear movement of the sensing element hub371, as shown in FIG. 30.

When the drive gear 303 has rotated approximately 180 degrees, theintroducer needle 334 and the catheter 342 have exited the housing 302and are inserted in the skin in a substantially similar manner as in thefirst and second exemplary embodiments. Substantially simultaneously,the sensing element 372 has exited the housing 302 and is inserted inthe skin in a substantially similar manner to the introducer needle 334.

The torsion spring 381 continues to rotate the drive gear 303. Thelinking arm 351 moves the introducer hub 341 rearwardly, therebywithdrawing the introducer needle 334. The catheter hub 331 has passedover the hooks 387 and 388 at the end of the flexible arms 385 and 386and is prevented from rearward movement by the hooks 387 and 388, asshown in FIGS. 33 and 34.

After having rotated approximately 180 degrees, the slave gear teeth 307are not engaged with the drive gear teeth 306. Accordingly, the sensingelement linking arm 362 is not moved and the sensing element hub 371 isnot moved such that the sensing element 372 remains inserted in theskin.

Tubing 314 extends from the fluid connector 321 and is adapted toconnect to a pump. The tubing 314 is connected to the penetrating member317 extending from an end of the tubing 314. The penetrating member 317is adapted to penetrate the septum 315 disposed in the housing 302, asshown in FIGS. 31 and 32. The septum 315 seals a fluid channel 318disposed in the housing 302. A flexible base tubing 316 is disposed atan opposite end of the fluid channel 318 from the septum 315. Anopposite end of the flexible base tubing 316 is connected to an opening319 in the introducer hub 341. A fluid path is created from theconnector tubing 314, through the septum 315, through the fluid channel318, through the base tubing 316 and into the introducer hub 341,through the introducer needle 334 and into the catheter 342, as shown inFIGS. 31 and 32. The base tubing 316 is flexible such that the basetubing 316 moves with the introducer hub 341 between first and secondpositions, as shown in FIGS. 26, 33 and 34. The tubing 314 can beremoved from the housing 302 by squeezing the finger grips together 376and 377 to unlock the tabs 322 and 323 from the housing recesses 324 and325.

The exemplary embodiment described above can be adapted for use witheither intradermal or subcutaneous injections. In addition, a differentmethod of maintaining the fluid connection is possible other than usingthe tube 314, such as a sliding seal. Alternative methods can be usedfor connecting and disconnecting the fluid connector 321 to and from thehousing 302, and for connecting and disconnecting the locking member 391to and from the housing 302, such as a button or a dial.

Although the exemplary embodiment described above is an infusion set, itwill be apparent to those of ordinary skill in the art that theprinciples of the present invention are also applicable to patch pumps(self-contained infusion devices with integral reservoirs and pumpingmechanisms) and other types of medical infusion and injection devices.

Fourth Exemplary Embodiment

The fourth exemplary embodiment of an infusion set 401, as shown inFIGS. 36-39, is substantially similar to the infusion set 301 of thethird exemplary embodiment shown in FIGS. 23-35. Similar components areidentified with the same base number in the 400 series, e.g., 4xx. Thesensing element 472 is inserted by a sensing element introducer needlein a similar manner as the catheter 342 of the third exemplaryembodiment, instead of the sensing element itself being a sharps. Theremaining operation and structure of the infusion set 401 issubstantially similar to the infusion set 301 of the third exemplaryembodiment.

A locking member 491 is received in the housing recesses such that afriction fit is created therebetween. When the infusion set 401 is readyto be used, adhesive backing is removed from the housing 402 such thatthe housing can be disposed on the user's body at a desired location.Finger grips 476 and 477 connected to the housing 402 facilitate theuser's grip on the housing 402 while removing the locking member 491.The locking member 491 is removed from the housing 402, such that thelocking tabs are disengaged from the recesses in the drive and slavegears 403 and 404, respectively. The drive and slave gears 403 and 404are free to rotate after the locking tabs are removed from the drive andslave gear recesses and from the openings in the housing 402.

The torsion spring 481 causes the drive gear 403 to rotate when thelocking tabs have been removed from the recesses in the drive and slavegears 403 and 404. The introducer hub 441 and catheter hub 431 areinitially in a first position, as shown in FIGS. 36 and 37, proximatethe drive gear 403. As the drive gear 403 rotates, the catheter linkingarm 451 converts the rotation of the drive gear 403 into linear movementof the catheter introducer hub 441. The catheter linking arm 451 movesthe catheter introducer hub 441 linearly away from the drive gear 403.The catheter introducer hub 441 pushes the catheter hub 431 as thecatheter introducer hub 441 moves away from the drive gear 403. Theguide rails in the housing 402 facilitate linear movement of thecatheter introducer hub 441 and catheter hub 431.

Rotation of the drive gear 403 rotates the slave gear 404 due to theengagement between the drive gear teeth 406 and the slave gear teeth407. The sensing element linking arm 461 moves the sensing elementintroducer hub 493 as the slave gear 404 is rotated by the drive gear403. The sensing element introducer hub 493 pushes the sensing elementhub 471 as the sensing element introducer hub 493 moves away from theslave gear 404. The guide rails in the housing 402 facilitate linearmovement of the sensing element introducer hub 493 and the sensingelement hub 471.

When the drive gear 403 has rotated approximately 180 degrees, theintroducer needle and the catheter 442 have exited the housing 402 andare inserted in the skin in a substantially similar manner as in thefirst, second and third exemplary embodiments. Substantiallysimultaneously, the sensing element 472 has exited the housing 402 andis inserted in the skin in a substantially similar manner as theintroducer needle.

The torsion spring 481 continues to rotate the drive gear 403. Thelinking arm 451 moves the introducer hub 441 rearwardly, therebywithdrawing the introducer needle. The catheter hub 431 has passed overthe hooks 487 and 488 at the end of the flexible arms 485 and 486 and isprevented from rearward movement by the hooks 487 and 488.

After having rotated approximately 180 degrees, the slave gear teeth 407are still engaged with the drive gear teeth 406 as the slave gear teeth407 extend approximately 210 degrees around the outer perimeter of theslave gear 404, as shown in FIGS. 36 and 37. Accordingly, the slave gear404 is rotated approximately 30 degrees, such that the linking arm 461draws the sensing element introducer hub 493 rearwardly. The sensingelement hub 471 is prevented from rearward movement by hooks 467 and 468at the end of flexible arms 465 and 466, as shown in FIGS. 38 and 39.The rearward movement of the sensing element introducer hub 493 retractsthe sensing element introducer needle, thereby exposing the sensingelement (similar to the catheter being exposed in the previous exemplaryembodiments). For example, the 30 degree rotation of the slave gear 404slightly retracts the sensing element introducer needle to expose thetip and a small length (e.g., approximately 2 mm) of the sensing element472. Once the slave gear teeth 407 are no longer engaged with the drivegear teeth 406, as shown in FIG. 39, the sensing element introducer hub493 is no longer moved rearwardly.

The exemplary embodiment described above can be adapted for use witheither intradermal or subcutaneous injections. Although the exemplaryembodiment described above is an infusion set, it will be apparent tothose of ordinary skill in the art that the principles of the presentinvention are also applicable to patch pumps (self-contained infusiondevices with integral reservoirs and pumping mechanisms) and other typesof medical infusion and injection devices.

Fifth Exemplary Embodiment

The fifth exemplary embodiment of an infusion set 501, as shown in FIG.40, is substantially similar to the infusion sets 301 and 401 of thethird and fourth exemplary embodiments shown in FIGS. 23-39. Similarcomponents are identified with the same base number in the 500 series,e.g., 5xx. The sensing element 572 is inserted by a sensing elementintroducer needle in a similar manner as in the fourth exemplaryembodiment. Instead of using a slave gear, the sensing elementintroducer hub 593 and the sensing element hub 571 are independentlydriven by a second torsion spring 582.

A first torsion spring 581 drives the catheter introducer hub 541 andthe catheter hub 531 as in the previous exemplary embodiments.

The second torsion spring 582 separately drives the sensing elementintroducer hub 593 and the sensing element hub 571 in a substantiallysimilar manner to the first torsion spring 581.

The infusion set 501 preferably is packaged in a sterile manner with aninfusion pump (not shown) already connected to the tubing 514. A lockingmember 591 is received in the housing recesses such that a friction fitis created therebetween. When the infusion set 501 is ready to be used,an adhesive backing (not shown) is removed from the housing 502 suchthat the housing can be disposed on the user's body at a desiredlocation. Finger grips 576 and 577 connected to the housing 502facilitate the user's grip on the housing 502 while removing the lockingmember 591. The locking member 591 is removed from the housing 502, suchthat the locking tabs are disengaged from the recesses in the first andsecond drive discs 503 and 504, respectively. The first and second drivediscs 503 and 504 are free to rotate after the locking tabs are removedfrom the first and second drive disc recesses and from the openings inthe housing 502.

The second torsion spring 581 causes the second drive disc 505 to rotatewhen the locking tabs have been removed from the recesses in the firstand second drive discs 503 and 504. The sensing element introducer hub593 and sensing element hub 571 are initially in a first position, asshown in FIG. 40, proximate the second drive disc 504. As the seconddrive disc 504 rotates, the sensing element linking arm 561 converts therotation of the second drive disc 504 into linear movement of thesensing element introducer hub 593. The sensing element linking arm 561moves the sensing element introducer hub 593 linearly away from thesecond drive disc 504. The sensing element introducer hub 593 pushes thesensing element hub 571 as the sensing element introducer hub 593 movesaway from the second drive disc 504. The guide rails in the housing 502facilitate linear movement of the sensing element introducer hub 593 andthe sensing element hub 571.

When the second drive disc 504 has rotated approximately 180 degrees,the introducer needle and the sensing element 572 have exited thehousing 502 and are inserted in the skin in a substantially similarmanner as in the first, second, third and fourth exemplary embodiments.Substantially simultaneously, the catheter 542 and catheter introducerneedle have exited the housing 502 and are inserted in the skin.

The second torsion spring 582 continues to rotate the second drive disc504. The sensing element linking arm 561 moves the sensing elementintroducer hub 593 rearwardly, thereby withdrawing the sensing elementintroducer needle. The sensing element 572 remains inserted under thesurface of the skin. The sensing element hub 571 has passed over thehooks 567 and 568 at the end of the flexible arms 565 and 566 and isprevented from rearward movement by the hooks 567 and 568.

The second torsion spring 582 can be set to a different deflection ratiothan the first torsion spring 581. For example, the first torsion spring581 can be set for 180 degrees of travel, such that the first 90 degreesinserts the catheter introducer needle and catheter 542 and the second90 degrees retracts the catheter introducer needle into the housing 502.The second torsion spring 582 can be set for 120 degrees of travel. Thefirst 90 degrees inserts the sensing element introducer needle andsensing element 572. The remaining 30 degrees of travel slightlyretracts the sensing element introducer needle to expose the tip and asmall length (e.g., approximately 2 mm) of the sensing element 572.

The exemplary embodiment described above can be adapted for use witheither intradermal or subcutaneous injections. Although the exemplaryembodiment described above is an infusion set, it will be apparent tothose of ordinary skill in the art that the principles of the presentinvention are also applicable to patch pumps (self-contained infusiondevices with integral reservoirs and pumping mechanisms) and other typesof medical infusion and injection devices.

The foregoing embodiments and advantages are merely exemplary and arenot to be construed as limiting the scope of the present invention. Thedescription of exemplary embodiments of the present invention isintended to be illustrative, and not to limit the scope of the presentinvention. Various modifications, alternatives and variations will beapparent to those of ordinary skill in the art, and are intended to fallwithin the scope of the appended claims and their equivalents.

What is claimed is:
 1. An infusion set, comprising: a base; a flexiblecatheter movable from a first catheter position disposed substantiallyentirely within said base to a second catheter position in which a freeend of said catheter is disposed externally of said base; an introducerneedle located within said catheter and movable between a firstintroducer needle position disposed substantially entirely within saidbase and a second introducer needle position in which a free end of saidintroducer needle is disposed externally of said base; a torsion springfor moving said catheter from said first to said second catheterposition and said introducer needle from said first to said secondintroducer needle position to facilitate insertion of said catheter,said introducer needle thereafter being moved by said torsion springback toward said first introducer needle position to store saidintroducer needle within said base with said free end of said catheterremaining disposed externally of said base; and a mechanical linkage forcoupling said torsion spring to said introducer needle, said mechanicallinkage comprising a first member coupled to said torsion spring forbeing rotated thereby and a second member coupled to said first memberat a fixed point thereon and to said introducer needle.
 2. The infusionset of claim 1, wherein said torsion spring is preloaded.
 3. Theinfusion set of claim 1, wherein said first member comprises a disc. 4.The infusion set of claim 1, wherein said second member comprises alinking arm.
 5. The infusion set of claim 1, wherein said first membercomprises a disc and said second member comprises a linking arm.
 6. Theinfusion set of claim 1, wherein: said introducer needle is carried byan introducer hub; and said second member is coupled to said to saidintroducer needle via said introducer hub.
 7. The infusion set of claim1, wherein said first member and said second member together form arotary crank mechanism for converting rotary motion from said torsionspring to linear motion of said introducer needle.
 8. The infusion setof claim 1, wherein: said wherein said first member comprises a firstgear; and a second gear is engaged with said first gear to move asensing element from a first position stored within said base to asecond position external to said base.
 9. The infusion set of claim 1,wherein said torsion spring is activated by a button movably connectedto said base.
 10. The infusion set of claim 1, wherein: a fluidconnector is removably connected to said base; and said torsion springis activated by movement of said fluid connector.
 11. The infusion setof claim 1, wherein a second torsion spring is activated to move asensing element from a first position stored within said base to asecond position external to said base.
 12. A method for inserting aflexible catheter of an infusion set, comprising disposing the infusionset on a skin surface at an injection site; inserting an introducerneedle and the flexible catheter through the skin surface uponactivation of a torsion spring disposed within the infusion set andcoupled to the introducer needle via a rotary crank mechanism;retracting the inserted introducer needle through the catheter bycontinued movement of the spring and the rotary crank mechanism; andstoring the retracted introducer needle substantially entirely within abody of the infusion set.
 13. The method of claim 12, further comprisinginserting a sensing element through the skin surface by activating thetorsion spring or by activating a second torsion spring.
 14. An infusionset, comprising: a base; a flexible catheter movable from a firstcatheter position disposed substantially entirely within said base to asecond catheter position in which a free end of said catheter isdisposed externally of said base; an introducer needle located withinsaid catheter and movable between a first introducer needle positiondisposed substantially entirely within said base and a second introducerneedle position in which a free end of said introducer needle isdisposed externally of said base; and a spring for moving said catheterfrom said first to said second catheter position and said introducerneedle from said first to said second introducer needle position tofacilitate insertion of said catheter, said introducer needle thereafterbeing moved by said spring back toward said first introducer needleposition to store said introducer needle within said base with said freeend of said catheter remaining disposed externally of said base; whereinsaid spring is activated by a button movably connected to said base. 15.The infusion set of claim 14, wherein said spring comprises a torsionspring, and further comprising a mechanical linkage for coupling saidtorsion spring to said introducer needle, said mechanical linkagecomprising a first member coupled to said torsion spring for beingrotated thereby and a second member coupled to said first member at afixed point thereon and to said introducer needle.
 16. An infusion set,comprising: a base; a flexible catheter movable from a first catheterposition disposed substantially entirely within said base to a secondcatheter position in which a free end of said catheter is disposedexternally of said base; an introducer needle located within saidcatheter and movable between a first introducer needle position disposedsubstantially entirely within said base and a second introducer needleposition in which a free end of said introducer needle is disposedexternally of said base; and a spring for moving said catheter from saidfirst to said second catheter position and said introducer needle fromsaid first to said second introducer needle position to facilitateinsertion of said catheter, said introducer needle thereafter beingmoved by said spring back toward said first introducer needle positionto store said introducer needle within said base with said free end ofsaid catheter remaining disposed externally of said base; wherein afluid connector is removably connected to said base; and said spring isactivated by movement of said fluid connector.
 17. The infusion set ofclaim 16, wherein said spring comprises a torsion spring, and furthercomprising a mechanical linkage for coupling said torsion spring to saidintroducer needle, said mechanical linkage comprising a first membercoupled to said torsion spring for being rotated thereby and a secondmember coupled to said first member at a fixed point thereon and to saidintroducer needle.
 18. An infusion set, comprising: a base; a flexiblecatheter movable from a first catheter position disposed substantiallyentirely within said base to a second catheter position in which a freeend of said catheter is disposed externally of said base; an introducerneedle located within said catheter and movable between a firstintroducer needle position disposed substantially entirely within saidbase and a second introducer needle position in which a free end of saidintroducer needle is disposed externally of said base; a first springfor moving said catheter from said first to said second catheterposition and said introducer needle from said first to said secondintroducer needle position to facilitate insertion of said catheter,said introducer needle thereafter being moved by said spring back towardsaid first introducer needle position to store said introducer needlewithin said base with said free end of said catheter remaining disposedexternally of said base; and a second spring that is activated to move asensing element from a first position stored within said base and asecond position in which a free end of said sensing element is disposedexternally of said base.
 19. The infusion set of claim 18, wherein saidfirst spring comprises a torsion spring, and further comprising amechanical linkage for coupling said torsion spring to said introducerneedle, said mechanical linkage comprising a first member coupled tosaid torsion spring for being rotated thereby and a second membercoupled to said first member at a fixed point thereon and to saidintroducer needle.